Regensburg 2010 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 4: Focus: Structure and Dynamics of Responsive Hydrogels II

CPP 4.6: Talk

Monday, March 22, 2010, 15:30–15:45, H37

Structure and response of pNIPAM microgels loaded with gold particles under thermal and optical stimuli — •Adrian Carl and Regine von Klitzing — Stranski-Laboratorium, Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 124, 10623 Berlin

Gold particles as well as pNIPAM microgels have been studied separately over the last decade. We studied the changes in thermal and optical responsivity of several composite particles compared to the properties of separate materials. Gold nanospheres and nanorods (AuNPs) were synthesised in the presence of pNIPAM microgels which contain different amounts of charged comonomers.

The influence of the gold particle shape and particle number on the swelling behaviour was studied by DLS measurements at two different wavelengths to investigate possible surface plasmon resonance effects. In order to obtain information about the distribution of the AuNPs inside of the microgel network, AFM, TEM and SAXS measurements were applied. During the phase transition of the microgels from swollen to collapsed state in the temperature range of 30-40^∘C (depending on the comonomers used), a wide broadening of the SPR-band in the UV-VIS spectra indicated a strong reversible interaction of the AuNPs.

The optical responsivity was further examined by turbidity measurements and a 2-laser DLS apparatus.

1 Karg, M.  Pastoriza-Santos, I.  Rodriguez-Gonzalez, B.; von Klitzing, R.  Wellert, S.  Hellweg, T. Langmuir 2008, 24, 6300-6306

2 Eustis, S.  El-Sayed, M. A. Chem. Soc. Rev. 2006, 35, 209-217